This invention pertains to compositions and methods for detecting and killing termites.
The Formosan subterranean termite, Coptotermes formosanus Shiraki, is a major worldwide pest that attacks both living trees and structural wood. Unlike other subterranean termites, the Formosan termite can establish a colony that does not touch the ground.
Coptotermes formosanus is native to southeast Asia, but is now also found in Hawaii, along the southeastern Atlantic coast of the United States, and in the Gulf South of the United States. First discovered in the United States in 1965, C. formosanus has gradually expanded its geographic domain. The largest single locus of C. formosanus in the United States is in south Louisiana, with heavy infestations in Lake Charles and New Orleans. C. formosanus may in some cases displace native Reticulitermes spp.
C. formosanus continues to cause great structural damage to many buildings in the Lake Charles and New Orleans areas, including damage to many buildings of historic significance. There is particular concern for the future of New Orleans"" French Quarter, where many historic buildings are already severely damaged and would be quite expensive to repair.
Three principal methods have been used in the past to control Coptotermes: (1) chemical and physical barriers to prevent termites from attacking wood, (2) wood preservatives and termiticides used to protect infested or susceptible wood, and (3) destruction of a termite colony by excavation of the nest.
Chemical barriers and termiticides have generated public concern over environmental safety.
In China excavation of the nest has been one of the main methods used to control Formosan termites. However, locating a termite nest is typically very time-consuming, limiting the usefulness of the practice.
Using a bait to deliver a termiticide has several advantages. Baits typically require only a small amount of the toxicant, and they target only the insects that feed on the bait (or are re-fed the bait by nest mates). Thus non-target organisms are not affected, diminishing the environmental impact of the toxicants. Use of a bait can make it unnecessary to locate the nest, because many termites, including Formosan termites, engage in trophallaxis (transfer of food to other colony members). Thus the toxicant may be spread throughout a colony after feeding by only a few foraging termites. Bait methods have previously been used to detect and experimentally control subterranean termites, and to trap termites for studies on termite ecology.
A major problem with existing baiting techniques against Coptotermes species has been inconsistent bait acceptance. Baits placed within termite galleries are often bypassed and left uneaten. The use of termite baits is different from the use of ant baits and cockroach baits, because it is usually not possible to remove competing food sources for termites. Attractants and feeding stimulants have sometimes increased the consistency of bait acceptance, but there remains a continuing need for improved termite baits.
There is a continuing need for improved techniques for killing termites. There is also a continuing need for improved methods for detecting termite nests. Current detection techniques rely primarily on visual inspection. Unfortunately, termite nests are frequently overlooked by visual inspection techniques. Formosan termite nests, in particular, can often be outwardly invisible for years, while the termites cause considerable unseen damage.
C. formosanus uses soil, masticated wood, and excrement, cemented by saliva and excrement, to make its nests, termed xe2x80x9ccartons.xe2x80x9d Gallery and shelter tube systems connect primary nests to accessory nests and feeding sites. C. formosanus colonies continually expand their foraging areas by enlarging the nest, or by building accessory nests.
J. Chen et al., xe2x80x9cNaphthalene in Formosan Subterranean Termites and Their Nest Carton,xe2x80x9d Poster Presentation, 213th American Chemical Society National Meeting (San Francisco, Calif., April 1997) presented some of the results disclosed in the present specification.
U.S. Pat. No. 5,637,298 discloses that 2-naphthalenemethanol and certain derivatives of 2-naphthalenemethanol are termite attractants, and that these attractants may be used to increase bait acceptance by termites.
G. Henderson, xe2x80x9cNo Fungus Among Us,xe2x80x9d PCT Pest Control Technology, pp. 60-61 (May 1997) states that four unidentified chemicals used by Formosan termites to inhibit fungal growth had been identified, and that the chemicals were toxic to ants.
Both the introduced Formosan subterranean termite, Coptotermes formosanus Shiraki, and subterranean termites in the genus Reticulitermes exhibit trail-following behaviors. M. Tokoro et al., xe2x80x9cIsolation and primary structure of trail pheromone of the termite, Coptotermes formosanus Shiraki (Isoptera: Rhinotermitidae),xe2x80x9d Wood Res., vol. 76, pp. 29-38 (1989) reported isolation of the trail pheromone from C. formosanus, and identified it as (Z,Z,E)-3,6,8-dodecatrien-1-ol (DTE-OH), which has also been reported to be the trail-following pheromone of R. virginicus (Banks) and R. santonensis (Feytaud). See F. Matsumura et al., xe2x80x9cIsolation and Identification of Termite Trail-Following Pheromone,xe2x80x9d Nature, vol. 219, pp. 963-964 (1968); and N. Laduguie et al., xe2x80x9cIsolation and Identification of (3Z,6Z,8E)-3,6,8-dodecatrien-1-ol in Reticulitermes santonensis Feytaud (Isoptera, Rhinotermitidae): Roles in Worker Trail-Following and in Alate Sex-Attraction Behavior,xe2x80x9d J. Insect Physiol., vol. 40, pp. 781-787 (1994).
Termites have also showed trail-following activity in response to certain non-pheromone chemicals. The trail-following activity of several synthesized (Z)4-phenyl-3-buten-1-ol derivatives has been tested for five species of subterranean termites in the genera of Coptotermes, Reticulitermes, and Schedorhinotermes. See G. Prestwich et al., xe2x80x9cStructure-activity relationships among aromatic analogs of the trail-following pheromone of subterranean termites,xe2x80x9d J. Chem. Ecol., vol. 10, pp. 1201-1217 (1984).
Several glycol compounds have been reported to act as trail following substances for termites. G. Becker et al., xe2x80x9cUntersuchungen xc3xcber das verhalten von Termiten gegenxc3xcber einigen spurbildenden Stoffen,xe2x80x9d Z. Angem. Entomol., vol. 53, pp. 400-436 (1968). (See English language summary, pp. 433-434.)
M. Rust et al., xe2x80x9cEnhancing Foraging of Western Subterranean Termites (Isoptera: Rhinotermitidae) in Arid Environments,xe2x80x9d Sociobiology, vol. 28, pp. 275-286 (1996) reported that foraging of the western subterranean termite Reticulitermes hesperus was enhanced by placing into sand extracts from the brown rot fungus Gloeophyllum trabeum, and that the fungal extract plume in the soil could assist worker termites in locating monitoring or bait stations.
J. Gassett et al., xe2x80x9cVolatile Compounds from the Forehead Region of Male White-Tailed Deer (Odocoileus virginianus),xe2x80x9d J. Chem. Ecol., vol. 23, pp. 569-578 (1997) reported several compounds identified in secretions from the forehead and back of the male white-tailed deer, including naphthalene.
Papermate(copyright) ball-point pen ink is known to elicit trail following behaviors in introduced Formosan subterranean termites and native subterranean termites. (Harry McMennemy, private communication.) However, the active ingredient has not previously been identified.
We have discovered several previously unknown components of termite nest cartons. These compounds may be used as an attractant for termite baits, as a feeding stimulant, as the basis for novel chemical methods of detecting termite nests, and as the basis for novel biological methods of controlling termites.
As one example of these newly-discovered components, we have for the first time identified and quantitatively measured naphthalene as a compound present in termite cartons. Naphthalene has been identified in colonies from Florida, Hawaii, and Louisiana by gas chromatography-mass spectrometry (GC-MS).